1. Field of the Invention
The invention relates to a novel microbiological process for the terminal oxidation of alkyl groups of heterocycles to carboxylic acid.
2. Background Art
Thorough studies for the microbiological oxidation of alkyl groups in aliphatic hydrocarbons have been performed, among others, with the microorganism strain Pseudomonas oleovorans.
Regarding Pseudomonas oleovorans ATCC 8062 and ATCC 29347, it is known that the biochemical oxidation of alkanes proceeds in three steps to the corresponding acid. By the action of the alkane hydroxylase complex, first the corresponding alcohol results, which then in two steps, catalyzed by an alcohol dehydrogenase and an aldehyde dehydrogenase, is converted to the acid.
In this strain the genes, which are responsible for the enzymes of this oxidation, are on the plasmid OCT [Witholt et al., TIBTECH, Vol. 8, (1990), pp. 46 to 52].
The microbiological oxidation of alkyl groups to the corresponding acids by Pseudomonas oleovorans so far has been described only in compound with linearly saturated alkyl groups with 6 to 12 carbon atoms and with ethyl benzene [Fukuda et al., Agric. Biol. Chem. 53 (12), (1989), pp. 3293 to 3299].
The oxidation of alkyl-substituted cyclic aromatic or saturated hydrocarbons to the corresponding carboxylic acid with alkane-utilizing microorganisms such as Rhodococcus, Mycobacterium and Pseudomonas is described by Raymond, R. L., Process Biochemistry (1969), pp. 71 to 74.
The disadvantages of this process are that the reaction is not specific for alkyl groups with more than two carbon atoms, that ring cleavages can also occur and also that methyl groups in aromatic hydrocarbon compounds are oxidized.